New ping narrows MH370 search

New ping narrows MH370 search - The West Australian

The British navy oceanographic survey ship HMS Echo has been diverted to join Ocean Shield to survey the ocean floor in the area where searchers suspect the wreckage of MH370 rests.

HMS Echo was racing to the area overnight where the black box pings have been detected in the past five days.

Another ping was detected by an RAAF AP-3C Orion plane yesterday afternoon.

Echo is designed to map the ocean floor and may detect the wreckage. It is able to sweep a wide area with a multi-beam echo sounder that is best described as a radar scan of the ocean bottom.

Winthrop professor of coastal oceanography at the University of WA Charitha Pattiaratchi said the great advantage of HMS Echo was that it could work faster and cover a bigger area than any submersible and results could be seen in real time.

"It is of lower resolution than the Blueflin-21, but it can pick up an object like a large aircraft," he said.

The ocean in the area is 4500m deep and is covered in silt to a depth of 20m.

Ocean Shield has the Bluefin 21 aboard and this autonomous underwater vehicle can operate to 4500m and scan the seabed in detail.

The Bluefin 21 works slowly and has to be retrieved for results to be downloaded.

Referring to the echo scan from the British navy ship, Professor Pattiaratchi said the silt bottom would give a "softer" return but a metal plane would be "sharper".

"It will give the searchers a broad, lower resolution paint brush of the bottom," he said.

The search for the Malaysia Airlines Boeing 777 is divided into two sections.

The first, about 1000km west of Exmouth, is where searchers believe the main body of wreckage is.

About 700km further west is the much bigger area of 57,923sqkm where it is believed the main area of floating debris may be found.

Although it is believed the MH370 crashed in the middle of the clockwise eddy current, tropical cyclone Gillian passed through the area late last month with winds close to 190km/h.

In a twist, Gillian approached the area from the north before veering west, almost over where Ocean Shield is searching for more pings from the black boxes.

This would have tended to take the debris to the west, though the cyclone itself rotates clockwise.

Professor Pattiaratchi cautioned the storm would have probably pummelled any debris and caused it to sink.

Ten military aircraft, four civil aircraft and 13 ships were involved in yesterday's search for MH370, which disappeared with 239 passengers and crew on March 8.

Aircraft and ships spotted many objects on Tuesday but none were believed to be associated with MH370.